The 80486 Microprocessor Architecture & Features

The 80486 Microprocessor Architecture & Features – The 80486 Microprocessor is a 32-bit microprocessor. It is packaged in a 168-pin grid array package. The 24MHz, 33MHz, 50MHz, and 100MHz versions of the 80486 microprocessor are available.

Architecture of the 80486 Microprocessor

The 32-bit pipelined architecture of the 80486 microprocessor is shown in Figure 1. The internal architecture of the 80486 microprocessor can be broadly classified into three sections.

1. Bus Interface Unit
2. Execution and Control Unit
3. Floating Point Unit

Bus Interface Unit

This unit is primarily responsible for coordinating all the bus activities. The address driver interfaces the internal 32-bit address output of the cache unit with the system bus.

Execution and Control Unit

The control signals are provided by this unit to complete the execution of the instruction.

Floating Point Unit

It is responsible for carrying out mathematical data processing at a higher speed than the ALU, with its built-in floating-point algorithm.

Features of the 80486 Microprocessor

The 80486 microprocessor has the following features:

1. The 80486 microprocessor is the first microprocessor with an in-built floating point unit.
2. The five-stage pipeline was introduced by the 80486 microprocessor.
3. It is the first microprocessor to have an on-chip cache.
4. Boundary scan test and online parity check features were introduced in the 80486 microprocessor to make it more susceptible to a fault-tolerant architecture.